US 3683481 A
A tube expander apparatus and method for expanding heat exchange tubing into pressure assembly with a header bore. Expanding power is supplied by hydraulically powered motive means supplied with pressurized fluid from electrically driven pump means. Torque sensing means is employed to arm the automatic cycling of the expanding operation and to condition the apparatus for restoration to starting position at the end of the tube-expanding cycle. The expansion cycle can be held in dwell condition at any stage at the user's option for any purpose. Gripper means swivelly mounted on the expander is effective to hold the tube against rotation during initial stages of the cycle should this be desirable.
Description (OCR text may contain errors)
United States Patent- Blackburn et al. [4 1 Aug. 15, 1972  APPARATUS FOR EXPANDING TUBES 3,628,227 12/ 197i Blackburn et al. ..29/ 157.4
 Inventors: Marvin J. Blackburn, Pasadena mary Exammer-Thomas H. Eager Angel, Attorney-W. D. Sellers et al.
731' Vernon Tool Co., Ltd., Alhambra, v[571 ABSTRACT A tube expander apparatus and method for expanding 2 Marc heat exchange tubing into pressure assembly with a [2 1 h 11971 header bore. Expanding power is supplied by hydrauli-  Appl. No.: 122,836 cally powered motive means supplied with pressurized fluid from electrically driven pump means. Torque Related pp Dita sensing means is employed to arm the automatic  Division of Ser. No. 803,375, Feb. 28, 1969, cyc'mg expandmg. Pat No 3 628 227 the apparatus for restoration to starting position at the end of the tube-expanding cycle. The expansion cycle can be held in dwell condition at any stage at the  US. Cl. "297/202 D useris option for any purpose Gripper means Swivel), [5 l] Int. Cl .323]! 15/26, B23p 19/04 mounted on the expander is effective to hold the tube Fleld of Search D, 157.4, R against rotation Stages of the cycle should this be desirable. R f ited  e C 21 Claims, 13 Drawing Figures UNITED STATES PATENTS PAIENTEDAU: 15 I972 SHEET 2 [IF 4 INVENTORS. W
WW w MAW we a w 47 7 APPARATUS FOR EXPANDING TUBES This application is a division of our copending application for US. Letters Pat. Ser. No. 803,375, filed Feb. 1969, now Pat. No. 3,628,227, patented Dec. 21,
This invention relates to tube expanders and more particularly to an improved apparatus for expanding the end of heat exchange tubing into assembled relation to a header in an automatic cycle and including provision for manually controlled interruption of the automatic cycle at any stage.
Various types of equipment and modes of operation have been proposed heretofore to expand exchanger tubes against seating bores therefor in header plates, but such equipment is subject to various shortcomings and disadvantages avoided by the present invention. Perhaps the most satisfactory prior construction is that disclosed in the Stary US. Pat. No. 2,690,205. The present apparatus and method have certain features in common with the apparatus there disclosed but include numerous new and improved features having decided advantages over the Stary expander. That apparatus is lacking in versatility and employs a complex control system subject to serious limitations. More specifically the Stary concept revolves around means for timing and measuring quantities of work performed on metal undergoing working and intended to terminate the expansion cycle when this quantity of work has been performed. Typically, a portion of hydraulic fluid employed to work the metal is bled off at a predetermined rate and utilized to measure a time period. There is no way of interrupting either the operation of the timer or a tube-expanding cycle for any purpose as is highly essential under certain operating conditions commonly encountered in the use of that equipment.
Other disadvantages of prior expander equipment avoided by this invention include the lack of any provision for shifting a tube relative to the header and into proper expanding position during the expanding operation, nor does prior apparatus include means for holding the tube against rotation until such time as it has been expanded into firm gripping relation with the header bore. Additionally, prior equipment lacks satisfactory means for suspending the expander tool selectively at a desired operating height and shifting it to a wide range of other operating heights while fully counterbalanced.
Still another unique feature of this invention is the provision of simple means for interrupting the advance or retraction of the expanding mandrel at any stage of the operating cycle and for locking it in this dwell position while the expander rollers continue in operation either to relieve stresses, to iron out high areas in the surface of the tubing, or to maintain a grip on the tubing while shifting it to a desired assembly position relative to the header. Means provided for these and the like purposes include valve means for controlling the mandrel reciprocating motor whereby this valve moves quickly and automatically to its neutral position when de-energized wherein it is effective to block all fluid flow to and from the mandrel reciprocating means. If the expander has reached its initial tube-gripping position, this grip can be positively maintained while the operator applies axial force to the tool to shift the tube into a proper assembly position and to hold it in this position as further advance of the mandrel is resumed.
In this manner, a single operator in charge of the tool can utilize the expander tool to grip the tube and hold it in a proper position relative to the header as the tool resumes its normal expanding operation.
The present equipment also features a simple, unique and highly effective means for measuring mandrel torque as developed in expanding the tube. Thus, when the sensed torque, as detennined by the electrical power requirements of the motor-pump unit supplying pressurized fluid to the mandrel drive motor reaches a predetermined value, load-sensing means operates automatically to arm the automatic control circuit for the expander. Pressure responsive switch means in circuit with the arming switch responds to a preselected hydraulic fluid pressure, provided the circuit is armed, to initiate a sequence of operations including the automatic termination of the expansion cycle and the return of all components to their initial positions.
It is therefore a primary object of the present invention to provide a new and improved apparatus for expanding heat exchange tubing into a header bore.
Another object of the invention is the provision of self-contained mobile automatic tube-expanding apparatus having load-sensing means responsive to the torque of the expander to arm an automatic cycle control circuit. Another object of the invention is the provision of hydraulically powered tube expander apparatus having means carried on the expander tool for holding a tube against rotation until expanded into gripping relation with a header bore.
Another object of the invention is the provision of a tube-expanding apparatus and method featuring simple, easily controlled means for interrupting the reciprocation of the expander mandrel without interrupting the rotation of the tube-expanding rollers.
Another object of the invention is the provision of a self-contained mobile tube expander apparatus having improved means for supporting the expander tool selectively at various elevations and at different distances from the end of a tube undergoing expansion.
Another object of the invention is the provision of tube expander apparatus utilizing a single electrically driven motor to operate a plurality of hydraulic pumps each connected with a separate hydraulic motor and including load-sensing means in circuit with the driving electric motor and operative to arm an automatic cycle control circuit for said apparatus.
These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawings to which they relate.
Referring now to the drawing in which a preferred embodiment of the invenn'on is illustrated:
FIG. 1 is an elevational view partly in section showing a preferred embodiment of the invention in use to expand tubing;
FIG. 2 is a cross-sectional view on a slightly enlarged scale taken along line 2-2 on FIG. 1;
FIG. 3 is an enlarged view of the expander tool per se on an enlarged scale with portions broken away to show constructional details;
FIG. 4 is a cross-sectional view taken along broken line4l-4 on FIG. 3;
FIG. 5 is a cross-sectional view on an enlarged scale showing details of the tool suspension trolley mechanism;
FIG. 6 is a cross-sectional view on an enlarged scale taken along line 66 on FIG. 5;
FIG. 7 is a longitudinal sectional view on an enlarged scale taken through the tube expander components per se and showing the position of the components with the expander retracted and the tube gripper relaxed;
FIG. 8 is a view similar to FIG. 7 but showing the tube expander fully expanded and the tube gripper in gripping position;
FIG. 9 is a cross-sectional view taken along line 99 on FIG. 7 showing the expander contracted;-
FIG. 10 is a cross-sectional view similar to FIG. 9 but showing the expander in an initial tube-gripping position;
FIG. 11 is a view similar to FIG. 10 but showing the tube more fully expanded;
FIG. 12 is a view taken along line l2-12 on FIG. 8; and
FIG. 13 is a schematic of the hydraulic and electrical controls.
APPARATUS IN GENERAL Referring more particularly initially to FIG. 1, there is shown a preferred embodiment of the invention apparatus, designated generally 10, equipped with a chassis 11 provided with swiveling rollers 12. Rigidly supported on chassis 11 is an inverted L-shaped bracket comprising a tubular vertical leg 13 and an inverted channel-shaped horizontal leg 14. A trolley mechanism 15 concealed by leg 14 includes pairs of rollers 16 (FIGS. 5 and 6) supported along the inturned lips of the channel member and having a downwardly projecting stem 18 supporting a pair of rollers 19 on a common pin. A suspension cable 20 for the expansion tool is trained over rollers 19. One end of this cable is secured to the bracket at the outer end of leg 14 and then passes over one of pulleys 19, about pulley block 21 attached to the expander tool, then upwardly over the other one of pulleys l9, downwardly over pulley 22 at the upper end of bracket tube 13, through the counterweight pulley block 23, and thence upwardly to anchor strap 24. Attached to the underside of pulley block 23 is a rod 25 on which is supported an appropriate number of individual counterweights 26 which can be added and removed through access part 28 as necessary to balance the weight of the tool. It will therefore be evident from the foregoing that the expander tool can be raised and lowered to different levels, as well as moved to and fro horizontally lengthwise of bracket leg 14 with very little effort.
Mounted on chassis 11 is a hydraulic fluid reservoir, a single electric motor 31 coupled to drive each of the hydraulic pumps 32 and 33, a four-way valve 34 and various control components housed within cabinet 35.
The expander tool proper, designated generally T, has a generally horizontally disposed main frame 38 along which the rotary hydraulic motor 39 is bodily reciprocated by the linear hydraulic motor 40. Motor 39 rotates a mandrel drive shaft 41 as will be described presently and is effective with other components to expand the end of each of the tubes 42 into pressure contact with a bore through header 43. Expander tool 10 is provided with a manipulating handgrip 45 at the rear end thereof equipped with a push-push type master control switch 46 and a normally closed hold" switch 47. These switches are connected to control cabinet 35 by cabling 48, the reciprocating motor 40 is connected to the hydraulic fluid circuit by flexible hoses 49, and rotary motor 39 is connected to these same fluid circuits by high pressure hoses 50.
THE EXPANDER TOOL Referring to FIGS. 3 through 12 and initially more particularly to FIG. 3, it is pointed out that main frame 38 of tool T includes a forward plate 53 and a rear plate 54 rigidly interconnected by three parallel tie-rods 55 forming a protective cage for motor 39. This motor is straddled by a U-shaped yoke 56 the legs of which extend horizontally along its opposite sides and having a cross-piece 56 bored to have sliding contact with one of tie-rods 55 in the manner best shown in FIGS. 1 and 4. The forward ends of yoke legs 56 are anchored to flanges projecting from the body of motor 39 with the result that the yoke and its sliding connection with tie red 55 is effective to anchor motor 39 against rotation while permitting it to slide to and fro lengthwise of the tie-rods.
Linear motor 40 has a piston 58 connected by its piston rod 59 to motor 39. The opposite sides of the piston are supplied with pressurized fluid through hydraulic fluid hoses 49, 49. It will therefore be clear that movement of piston 58 operates to reciprocate motor 39 lengthwise of the main frame and in a direction depending upon the side of the piston to which pressurized fluid is supplied.
The right-hand end of motor 39 has a drive shaft 41 in axial alignment with piston rod 59 and connected to the motor through a combination rotary and thrust bearing assembly 60 of well known construction.
Referring now more particularly to FIGS. 7 and 8, it will be noted that forward header plate 53 of the tool frame supports a tubular housing 62 enclosing a coupling 63 holding the inner end of tapered mandrel 64 coupled to motor shaft 41.
Joumaled in anti-friction bearing assembly 66 at the forward end of tubular housing 62 is a cage tube 67 surrounding the forward end of tapered mandrel 64. Cage tube 67 is provided with three elongated slots 68 having inwardly projecting lips 70 along their opposite lateral edges cooperating with mandrel 64 to hold rollers 69 captive within the slots. Further retaining assistance for the rollers is provided by a resilient sleeve 71 embracing the inner smaller ends of the rollers. It will be understood that the taper of rollers 69 is opposite and complemental to the taper of mandrel 64 with the result that the surface of the rollers adjacent surface of tube 42 is generally parallel thereto. This is true except when the rollers are inclined slightly relative to the length of the mandrel for reasons well known to those skilled in this art.
A tube-gripping or holding accessory, designated generally 75, is also desirably present on the forward end of the tubular housing 62. This accessory serves an important function, particularly when expanding straight tubes to a header wherein the OD of the tube is less than the diameter of header bore 76. If the other end tube is not accessible or anchored to some other structure, it is likely to rotate within bore 76 making it impossible to start the expansion operation. In these circumstances, accessory 55 is operable to prevent tube rotation, a preferred embodiment being constructed and operating in the manner now to be described.
Accessory 75 includes a housing 78 seating loosely over a tubular boss 79 carried by the main frame and is held swivelly assembled thereto by means of the keeper screw 80 having its inner end seating loosely in an annular groove 81 formed in the exterior of boss 79. The forward end of housing 78 is formed with an angular recess 82 sized to telescope loosely over the foremost end of a tube 42 to be expanded, it being understood that these tubes are customarily assembled to header bores 76 with their forward ends projecting slightly beyond the outer face of the header.
Accessory housing 78 includes a pair of parallel lugs 84 between which is pivoted an operating lever 85 on a pin 86 (FIGS. 7, 12). The forward end of housing 78 is notched at 88 to receive the inwardly projecting end 87 of lever 85 and this end is so dimensioned as to engage the end rim of tube 42, bite into and clamp the tube against the portion of bore wall 76 remote from the gripping lever. FIG. 7 shows the gripping end 87 of the lever out of engagement with tube 42, whereas FIGS. 8 and 12 show lever end 87 pivoted counterclockwise to clamp tube 42 against bore 76. A stop Once on the side of operating lever 89 (FIG. 7) engages housing 78 while the expanding tool is being inserted into its operating position thereby avoiding having the lever 85 pivot to a position interfering with insertion of the expander. Once the tool has been inserted, lever 85 may be employed to rotate accessory 75 to any convenient operating position about'the axis of the expander.
THE AUTOMATIC CONTROL SYSTEM Referring now to FIG. 13, there is shown a schematic of a preferred automatic control for the expander apparatus. The three-phase power supply 90 includes a suitable control box 91 for the starter equipment of a motor 31 driving the hydraulic pumps 32, 33. Pump 32 has its inlet connected to the hydraulic fluid reservoir 30 and supplies pressurized fluid to rotary motor 39 by way of the customary pressure relief valve 92 and a manually adjustable flow regulator valve 93. The speed of motor 39 is regulatable by adjusting control 94 for valve 93. All spent pressurized fluid from valves 92, 93 and motor 39 returns to tank 30 in accordance with customary practice.
The pressurized fluid discharging from pump 33 passes to the linear motor cylinder 40 by way of pressure relief valve 96, four-way valve 34 and an adjustable pressure-compensating and temperature-compensating valve 97 having a manual regulating means 98 for varying the flow passing to the rear end of motor 40 to operate the expander in its advance direction. Also connected in the pressurized fluid line going to the advance end of motor 40 is a normally open pressure switch 100, a pressure gauge 101, and a recorder 102 to make a record of the operating cycle.
Four-way valve 34 is solenoid-operated and is springbiased to return to its central neutral position if both solenoids are de-energized. Under these conditions, all flow to and from motor 40 is blocked and the motor is locked rigidly against movement in either direction irrespective of the position it then occupies.
The normally open load-sensing switch 105 includes an operating coil 1 suitably coupled, as by a transformer not shown, to the power leads supplying electrical energy to motor 91 and functions to sense changes in the power supplied to this drive motor. The loadsensing control means includes conventional manually adjustable means, not shown, for changing the setting thereof to make switch 105 close when the power supply to motor 31 reaches a predetermined value bearing a known relationship to the torque force developed by motor 39 in driving mandrel 64 of the tube expander mechanism. In other words, experience gained in the use of the invention tube expander has shown that the electrical energy power requirements of the motor driving the two hydraulic pumps bears a definite relationship to the torque required to drive mandrel 64 in expanding a given diameter and wall thickness of tubing into its assembled condition. This information is used in setting load-sensing device 105 so that the latter closes and arms or conditions the automatic control circuitry proper to carry out an automatic operating cycle governing the functioning of the expander tool. As is made clear by FIG. 13, loadsensing switch 105 is here shown in series circuit with pressure-responsive switch 100 and is preferably set to close somewhat before attainment of the pressure selected to close the pressure switch.
Other components of the control circuitry include a push-push master control switch 46, the normally closed hold switch 46, both mounted on operating handle 45 of the expander tool, and the three relays R-l, R--2 and the time control relay designated TD. The normal inactive position of all three relays is that shown in FIG. 13. The R-l and R-2 relays change position immediately upon energization and de-energization, but the time delay relay is adjustable to delay shifting position for a variable period typically ranging between 0.0 and 1 second. During this time delay period the mandrel is automatically locked against axial movement but rotary motor 39 continues to rotate the expander rollers to smooth out any high areas in tube 42 which may be present at the end of the expanding operation. and to relieve stresses in the tubing due to the substantial metal working which has taken place. The several relays and other components are connected between normally hot bus and the common return bus 111, the various connections preferably being those shown in FIG. 13.
OPERATION Let it be assumed that the operator has inserted the expander end of tool T into the free end of a U-shaped tube 42 having its other end previously expanded into a permanent fit with a header. Let it further be assumed that the free end of the tube into which the expander has been inserted does not terminate slightly forwardly of the front face of header 43 as it should before being expanded. Under these circumstances, the expander tool is obtained to obtain a grip on tube 42 and utilize this grip to pull the tube forwardly until its end projects beyond the forward face of header 43 by the desired distance and is so held while being expanded into gripping relation with bore 76. The manner in which the tool is operated to accomplish this result is as follows: Starter control 91 for pump motor 30 is first operated to place this motor in operation and charging the hydraulic circuits with pressurized fluid. As this occurs, rotary motor 39 goes into operation to drive mandrel 64, then in its fully retracted position, the desired operating speed being achieved by adjusting the speed control 98 of valve 97. No pressurized fluid can reach linear motor 40 until the operator acts. The operator initiates the actual expansion operation by depressing push-push switch 46 to close this switch thereby supplying power to relay R-l causing this relay to shift to the left to supply power to the advance coil of the four-way valve 34 by way of the normally closed contacts of the de-energized R-l relay and closed hold switch 47. The four-way valve then moves to its advance position to supply pressurized fluid to the lefthand end of motor 40 causing its piston 58 to slowly advance the rotating motor 39 and mandrel 64 carried thereby to the right, as viewed in the drawings. As the smaller end of the mandrel advances, it forces rollers 69 outwardly into gripping relation with the interior of tubing 42. In the fully retracted and relaxed condition of the expander, the mandrel and rollers 69 are in the position shown in FIG. 9, but as the mandrel advances the rollers are forced outwardly until they engage the tube. When this occurs the rollers roll along the interior surface of the tube in the same direction as the mandrel. This operation is allowed to continue until the operator can sense that the rollers are firmly gripping tube 42. At this time the operator, without relaxing his grip on tool grip 45, depresses the button of normally closed switch 47 opening the latter and breaking the operating circuit of the advance" control of four-way valve 34. Immediately the spring bias forming part of this valve shifts the valve to its neutral position blocking both the supply and exhaust flow passages of motor 40 and locking this motor against movement in either direction so long as switch 47 is held open. However, the flow to rotary motor 39 continues to drive this motor and the firm grip of rollers 69 on tube 42 is maintained. The operator then applies a pulling force to the outer end of tool T through handgrip 45 until he observes that the outer end of tube 42 projects the desired distance beyond the front face of header 43. The opposite sides of the tube-holding accessory 75 are provided with viewing ports 113, and elsewhere if necessary, to provide the operator with a better and clearer view of the tube end. Once the tube has been pulled to a desired projecting position, the operator steadies the tool in this position and holds it firmly while relaxing his finger pressure on hold switch 47. As this switch closes, the four-way valve is reactivated to its advance position so that motor 40 resumes the advance of the mandrel lengthwise of rollers 69. The steady hold on the tube is required only for a short interval since the expander is substantially advanced to a position where tube 42 is in frictional contact with the bore wall.
Owing to the continuing rotation of the mandrel while being forcibly extended axially of the rollers, cold working of the tube is effective to expand it gradually into tighter and tighter pressure contact with bore 76. This working of the tube metal imposes an increasing torque load on mandrel 64 and on driving motor 39.
This increasing torque load is accompanied by a increasing electrical power demand on motor 31 driving pump 33. Eventually this increasing power demand reaches the value effective to close load-sensing switch 105. This switch is preferably set to close just after the tube has been expanded against the bore wall sufficiently to prevent rotation or spinning of the tube.
The closing of load-sensing switch 105 arms or conditions the automatic control circuit, activation of the latter being consummated by the closing of pressure switch to complete a power circuit through the coil of relay R-2. The operation of relay R-2 disrupts the power supply to the advance side of four-way valve 34 and energizes the coil of time delay relay TD. However, this relay does not shift position until expiration of a predetermined time delay selected in advance by the setting of this relay. At the expiration of the time delay, the TD relay shifts position, closing a power circuit through the solenoid at the left-hand end of four-way valve 34, thereby reversing the flow of pressurized fluid through motor 40 and retracting the mandrel. During the time period axial movement of the mandrel is stopped in its advance position, motor 39 continues to rotate the mandrel and the rollers with the result that the tube metal is given a final working operation smoothing the interior of the tube and equalizing stresses in the freshly worked metal.
As soon as the time delay relay shifts to its alternate or left-hand position as viewed in FIG. 13, the mandrel begins to retract, allowing rollers 69 to relax, and all parts of the system to continue toward their initial starting positions. When fully retracted and restored to these initial positions, the system may continue to operate with pressurized fluid being supplied to the right-hand end of motor 40 without risk of injury to the equipment since the pressure relief valves in the hydraulic circuits open in response to any rise in pressure above a safe condition, thereby allowing excess fluid to return to reservoir 30. Deactivation of motor 40 occurs when the operator presses the push-push switch 46 a second time thereby interrupting the power supply to the control circuit and de-energizing all three relay coils and allowing them to resume their normal positions illustrated in FIG. 13. As soon as the heavy torque load ceases on the mandrel, the load-responsive switch opens and so does pressure switch 100. Accordingly, both of these switches resume their original normal positions well before the mandrel reaches its retracted position.
Now let it be assumed that the operator wishes to expand a tube 42 which has an initial loose fit in bore 46 and is not anchored at any point along its length. In these circumstances, the initial expansion of roller 69 into contact with the tube is likely to grip and rotate the tube about its own axis. If this occurs, rollers 69 do not roll along the interior of the tube, and the tube is distorted into a triangular shape and it is impossible to expand it throughout its circumference into engagement with the bore wall. In these circumstances, no working of the tube metal occurs with the result that the torque forces do not build up in mandrel 64. Consequently, load-sensing device 105, 106 is not closed, the automatic control circuit is not armed and it is impossible to complete the expansion operation.
The foregoing undesirable results are safeguarded against in the present invention by employing the tubegripping accessory 75 attached to the forward end of the main frame of the expander. The operator simply grasps the handgrip end of lever 85 and pivots it about pivot pin 86 forcing end 87 of the lever against the protecting end of tube 42 thereby clamping the tube firmly against the remote side of bore 76. This tool is highly effective in clamping the tube and holding it against rotation with the result that rollers 69 roll along the interior of the tube forcing the entire end of the tube to expand uniformly into firm contact with the bore wall. Once this occurs, the pressure on lever 85 may be relaxed and the expander operates automatically in the meynener described above to complete expansion of the tu If at any time during the operation of the expander device it becomes desirable for any reason to interrupt either the advance of the mandrel or its retraction, the operator need but press button 47 to interrupt the power supplyto hydraulic valve 34 causing the latter to shift to its neutral position and lock motor 40 against movement in either direction so long as hold switch 47 is held open.
While the particular apparatus for expanding tubes herein shown and disclosed in detail are fiilly capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that they are merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the detail of construction or design herein shown other than as defined in the appended claims.
1. That improvement in apparatus for expanding tubing into a permanent junction with the sidewall of a bore in a header, said apparatus being of the type having a unitary assembly supported'for axial movement relative to a tube end to be expanded, said assembly having a main frame slidably supporting a rotary motor, power driven means for reciprocating said rotary motor lengthwise of said main frame, rotary tube expander means carried coaxially of and driven by said rotary motor and adapted to enter a tube end and expand the same against the bore of a header, said improvement comprising: means for controlling the operation of said apparatus including means to maintain said motor in operation to rotate said tube expander means while selectively locking said power driven reciprocating means stationary for a selected interval at the operators election thereby enabling the operator to employ the grip of the tube expander means on the tubing to shift the tube to a desired position relative to the header before resuming the tube expanding operation.
2. That improvement in tube expander apparatus as defined in claim 1 characterized in that said power driven reciprocating means comprises hydraulic motor means, and said control means for locking said motor means against reciprocation including operator manipulatable means for maintaining said hydraulic motor means charged full of non-circulating hydraulic fluid until such time as it is desired to resume reciprocation of said rotary motor lengthwise of said main frame.
3. That improvement in tube expander apparatus as defined in claim 2 characterized in that said control means for locking said hydraulic motor means against reciprocation is operable at any position and in either direction of travel of said hydraulic motor means.
d. That improvement in tube expander apparatus as defined in claim 3 characterized in that the mode of operation of the remainder of said control means is unaltered by reason of having the operating cycle interrupted by locking said power driven reciprocating means against reciprocation for a period of time and irrespective of the length of the locked phase.
5. That improvement in tube expander apparatus as defined in claim 2 characterized in that said control means includes electrically-controlled four-way valve means for said power driven reciprocating means.
6. That improvement in tube expander apparatus as defined in claim 5 characterized in that said four-way valve means automatically resumes the neutral position thereof with all passages blocked to flow when said valve means is de-energized, and said control means including deadrnan control means requiring intentional operation by the operator to maintain said valve means de-energized.
7. That improvement in apparatus for expanding tubing into a permanent junction with the sidewall of a bore in a header, said apparatus being of the type having a unitary assembly supported for axial movement relative to a tube end to be expanded, said assembly having a main frame slidably supporting a rotary motor, power driven means for reciprocating said rotary motor lengthwise of said main frame, rotary tube expander means carried coaxially of and driven by said rotary motor and adapted to enter a tube end and expand the same into a permanent union with the bore of a header, and electric power supply means to operate said apparatus, said improvement comprising torque-sensing switch means responsive to an increase in the torque load developed by said rotary motor incident to the loading of said rotary motor to work the metal of tubing undergoing expansion to arm said control means for automatic operation, and said control means including means controlled by said torque-sensing switch means to complete the tube expanding operation and to return the parts to their initial starting positions.
8. That improvement in tube expanding apparatus as defined in claim 7 characterized in that said torquesensing switch means includes means for sensing a predetermined torque load on said rotary motor and responsive thereto to shift said torque-sensing switch means to the non-normal condition thereof.
9. That improvement in tube expanding apparatus as defined in claim 8 characterized in that the control means for said apparatus includes pressure responsive switch means in circuit with said load sensing switch means and operable in response to a predetermined high pressure in the high pressure portion of said power driven reciprocating means to initiate restoration of said tube expander means to retracted collapsed position and to reset the components of said control means to their initial starting positions.
10. That improvement in tube expanding apparatus as defined in claim 9 characterized in that said control means includes timer means for maintaining said expander means extended and rotating for a predetermined time period after ceasing to expand the tube and before starting to retract and collapse said tube expander means thereby to assure completion of the tube expansion and to equalize stress in the tubing.
1 1. That improvement in tube expander apparatus as defined in claim 7 characterized in the provision of manually operable means to vary the operating rate of advance of said power driven reciprocating means, and separate control means for varying the rotational speed of said rotary motor means.
12. That improvement in tube expander apparatus as defined in claim 7 characterized in the provision of separate hydraulic pumps to supply pressurized fluid to said power driven reciprocating means and to said rotary motor means, electric motor means to drive each of said pumps and connected to receive power from a power source, and said torque-sensing switch means being arranged to sense changes in power consumption by said electric motor means.
13. That improvement in tube expander apparatus of the type having a horizontally disposed combined rotating and reciprocating tube expander, a mobile power supply and control chassis for said tube expander including hydraulic flow and electric control lines extending to said tube expander, inverted L-shaped bracket means rigidly supported on said mobile chassis and including springless weighted counterbalanced cable means adjustably supported on said bracket operable to support said tube expander in suspension in a wide range of different levels.
14. That improvement in tube expander apparatus as defined in claim 13 characterized in the provision of trolley means supported for rolling movement horizontally along the horizontal leg of said inverted L-shaped bracket, and said counterbalance cable means being trained over said trolley and so arranged that tube expander and said trolley means move laterally in unison without need for bodily movement of the entire apparatus.
15. That improvement in tube expander apparatus as defined in claim 12 characterized in that the vertical leg of said inverted L-shaped bracket is tubular and encloses and conceals the vertically moveable end of said counterweighted cable means.
16. That improvement as defined in claim 15 characterized in that said tubular vertical leg includes access port means through which the counterweights can be changed on said cable means.
17. That improvement in apparatus for expanding ing a unitary assembly supported for axial movement relative to a tube end to be expanded, said assembly having a main frame slidably supporting a rotary motor, power driven means for reciprocating said rotary motor lengthwise of said main frame, rotary tube expander means carried coaxially of and driven by said hydraulic motor and adapted to enter a tube end and to expand the same into the bore of a header: said improvement comprising gripper means carried by said tube expander means and operable to grip a tube and hold the same from rotating during initial stages of the expansion operation and before it has been expanded into firm gripping relation with a header bore.
18. That improvement defined in claim 17 characterized in that said gripper means includes means for ss ssaaasrsai aaaa m. sass; means adapted to grip the foremost end of a tube to be expanded and to hold the same against rotation until the tube has been expanded into firm gripping relation with the bore wall of a header.
19. That improvement defined in claim 17 characterized in that said gripper means includes means for holding the same detachably and swivelly connected to said tube expander concentrically thereof and in position to grip the adjacent end portion of a tube while the tube is being initially expanded into assembled relation with a header bore, and hand grip means carried by said gripper means and manipulatable to grip a tube end.
20. Tube expanding apparatus as defined in claim 17 characterized in the provision of first means for sensing an increase in the torque load on said rotary motor, means utilizing hydraulic fluid pressure to power said tube expander means, second means for sensing an increase in the hydraulic fluid pressure driving said tube expander means including means responsive to one of said first and second means to terminate a tube expansion cycle.
21. Tube expanding apparatus as defined in claim 20 characterized in that one of said first and second means includes means subject to one thereof reaching a predetermined load value as a prerequisite to the initiation of a tube expanding cycle.